Microwave antenna having a curved configuration

ABSTRACT

An electrosurgical energy generator apparatus includes a microwave generator configured to supply microwave energy and an RF generator configured to supply RF energy. A power supply is coupled to the microwave generator and the RF generator and is configured to supply power to each of the microwave and RF generators. A first output is coupled to the microwave generator and is configured to deliver microwave energy. A second output is coupled to the RF generator and is configured to deliver RF energy.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of Ser. No. 10/272,314with claims the benefit of and priority to U.S. Pat. No. 7,197,363,filed Oct. 15, 2002, which claims the benefit of priority of U.S.Provisional Patent Application Ser. No. 60/373,190 filed Apr. 16, 2002,the entirety of both of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates generally to microwave antenna probes which may beused in tissue ablation applications. More particularly, the inventionrelates to microwave antennas which have curved configurations forinsertion into tissue.

BACKGROUND OF THE INVENTION

In the treatment of diseases such as cancer, certain types of cancercells have been found to denature at elevated temperatures which areslightly lower than temperatures normally injurious to healthy cells.These types of treatments, known generally as hyperthermia therapy,typically utilize electromagnetic radiation to heat diseased cells totemperatures above 41° C. while maintaining adjacent healthy cells atlower temperatures where irreversible cell destruction will not occur.Other procedures utilizing electromagnetic radiation to heat tissue alsoinclude ablation and coagulation of the tissue. Such microwave ablationprocedures, e.g., such as those performed for menorrhagia, are typicallydone to ablate and coagulate the targeted tissue to denature or kill it.Many procedures and types of devices utilizing electromagnetic radiationtherapy are known in the art. Such microwave therapy is typically usedin the treatment of tissue and organs such as the prostate, heart, andliver.

One non-invasive procedure generally involves the treatment of tissue(e.g., a tumor) underlying the skin via the use of microwave energy. Themicrowave energy is able to non-invasively penetrate the skin to reachthe underlying tissue. However, this non-invasive procedure may resultin the unwanted heating of healthy tissue. Thus, the non-invasive use ofmicrowave energy requires a great deal of control. This is partly why amore direct and precise method of applying microwave radiation has beensought.

Presently, there are several types of microwave probes in use, e.g.,monopole, dipole, and helical. One type is a monopole antenna probe,which consists of a single, elongated microwave conductor exposed at theend of the probe. The probe is sometimes surrounded by a dielectricsleeve. The second type of microwave probe commonly used is a dipoleantenna, which consists of a coaxial construction having an innerconductor and an outer conductor with a dielectric separating a portionof the inner conductor and a portion of the outer conductor. In themonopole and dipole antenna probe, microwave energy generally radiatesperpendicularly from the axis of the conductor.

Because of the perpendicular pattern of microwave energy radiation,conventional antenna probes are typically designed to be inserteddirectly into the tissue, e.g., a tumor, to be radiated. However, suchtypical antenna probes commonly fail to provide uniform heating axiallyand/or radially about the effective length of the probe.

It is especially difficult to assess the extent to which the microwaveenergy will radiate into the surrounding tissue, i.e., it is difficultto determine the area or volume of surrounding tissue which will beablated. Furthermore, when conventional microwave antennas are inserteddirectly into the tissue, e.g., cancerous tissue, there is a danger ofdragging or pulling cancerous cells along the antenna body into otherparts of the body during insertion, placement, or removal of the antennaprobe.

One conventional method for inserting and/or localizing wires or guidesis described in U.S. Pat. No. 5,221,269 entitled “Guide for Localizing aNonpalpable Breast Lesion” to Miller et al. which is incorporated hereinby reference in its entirety. Miller describes a wire guide which isdelivered into breast tissue through a tubular introducer needle. Whendeployed, the wire guide cuts into and scribes a helical path about thetissue distal to a lesion while the remainder of the distal portion ofthe wire guide follows the path scribed by the distal tip and locksabout the tissue. However, Miller does not teach any structures forcurved microwave antennas or their methods of use for surroundingpredetermined regions of tissue for treatment.

U.S. Pat. No. 5,507,743 entitled “Coiled RF Electrode TreatmentApparatus” to Edwards et al., which is incorporated herein by referencein its entirety, describes an RF treatment apparatus for hyperthermia atlow temperature which is also able to effect microwave treatment via anRF indifferent electrode which forms a helical structure. However, theelectrode, which is deployed from an introducing catheter, comprises ahollow tubular structure with fluid ports defined along the structure.

Accordingly, there remains a need for a microwave antenna whichovercomes the problems discussed above. There also exists a need for amicrowave antenna which can be inserted into tissue and which produces aclearly defined area or volume of ablation. Moreover, there is also aneed for a microwave antenna which can ablate an area or volume oftissue without ever having to directly contact the ablated tissue.

SUMMARY OF THE INVENTION

A microwave ablation device is described below which is able to clearlydefine an ablation region by having the antenna surround at least amajority of the tissue to be ablated without the need to actuallypenetrate or contact the targeted region of tissue. This is accomplishedin part by a microwave antenna probe which has a curved antenna portionranging in size anywhere from several millimeters to several centimetersdepending upon the size of the tissue to be treated. Various conductivematerials may be used to fabricate the antenna, such as stainless steelor Nitinol. Moreover, a dielectric coating may be placed over at least amajority of curved antenna to aid with the insertion of the antenna intothe tissue as well as to aid in preventing the tissue from sticking tothe antenna.

The curved antenna portion is preferably curved to form a loop orenclosure which is selectively formed large enough for surrounding aregion of tissue. When microwave energy is delivered through thefeedline, any part of the feedline or antenna that completes theenclosure becomes part of the radiating portion. Rather than radiatingdirectly along the length of the antenna, as one skilled in the artwould normally expect, the curved configuration forms an ablation fieldor region defined by the curved antenna and any tissue enclosed withinthe ablation region becomes irradiated by the microwave energy. Thus,the curved antenna also serves as a boundary which is able to clearlydefine what tissue will be irradiated, thereby reducing the amount ofundesirable damage to healthy surrounding tissue. Furthermore, thecurved antenna also defines a predictable region of tissue outside theirradiated zone which will also be irradiated. This margin of tissue isgenerally very predictable and serves to treat the tissue a shortdistance outside the ablation region to ensure complete treatment of thearea.

The curved antenna may be formed into a variety of shapes so long as theantenna preferably forms a substantially enclosed loop or enclosure,i.e., the curved antenna surrounds at least a majority of the tissue tobe enclosed. Accordingly, the antenna may be formed into shapes such ascircles, ellipses, spirals, helixes, squares, rectangles, triangles,etc., various other polygonal or smooth shapes, and partial forms of thevarious shapes so long as a majority of the enclosed tissue issurrounded. The curved antenna may be looped or wound about the selectedtissue region anywhere from about 180° to 360° or greater, relative to acentral point defined by the curved antenna. The curved antenna ispreferably wound at an angle greater than 180°.

Multiple curved antennas may be used in conjunction with one another bypositioning separate antennas adjacently or at different anglesdepending upon the size and shape of the tissue to be treated. Moreover,other variations on the curved antenna may have a single antenna body orfeedline with multiple curved antennas extending therefrom.

To facilitate desirable placement and positioning of multiple antennaswithin the tissue to be treated, various alignment assembly devices maybe utilized. Such alignment devices may be used to align and securelyposition the antennas to form various ablation region depending upon thedesired results. Furthermore, the various alignment devices may be usedto align and position a single antenna or a plurality of antennasdeployed during a procedure.

Deployment and positioning of the microwave antennas may also beachieved through one of several different methods. For instance,antennas may be positioned within the tissue using introducers and wiresfor guiding placement of the antennas. Alternatively, other methods mayinvolve using RF energy to facilitate deployment within the tissue. Themicrowave antenna is preferably insulated along most of its length, butthe distal tip may be uninsulated such that the RF energy may be appliedthereto to provide a cutting mechanism through the tissue. The generatorused to supply the RF energy may be a separate unit or it may beintegrated with the microwave energy generator within a single unit.

Moreover, another variation which may be utilized involves creatingmultiple channels from a single unit by multiplexing and cycling theoutput. This is particularly useful when using multiple microwaveantennas. A channel splitter assembly may be used to create multiplechannels by using a single source. Any number of multiple outputs may beused depending upon the desired number of channels and the desiredeffects. Additionally, the rate of cycling may range anywhere fromseveral microseconds to several seconds over a treatment period ofseveral minutes or longer.

Additional features may also be employed, e.g., to enhance the safety ofthe microwave antennas. For instance, a connection mechanism may allowfor antenna connection with an outer shell of a conventional or customconnector. Such a feature may be configured to allow an electricalconnection upon fill deployment of the inner conductor of the curvedantenna and no electrical connection during antenna deployment.

Furthermore, the curved shape of the antenna may allow for variousapplications within the body aside from tumor ablation. For instance,the curved antenna may be used to treat or seal, e.g., aneurysms,malfunctioning vessels, fistulas, bone metastases, etc., among otherconditions or regions of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a variation of a microwave antenna assembly having acurved antenna.

FIG. 1B shows a cross-section of the feedline from the antenna assemblyof FIG. 1A.

FIGS. 1C and 1D show cross-sectional and end views, respectively, of avariation of the feedline having plated conductive layers to increaseenergy transmission.

FIGS. 2A to 2G show different variations which the curved microwaveantenna may embody.

FIGS. 2H to 2M show different variations of the microwave antenna withvariable antenna lengths.

FIG. 2N shows a variation of the microwave antenna having an inflatableballoon disposed about the curved antenna for changing the effectivemicrowave wavelength.

FIGS. 2O and 2P show another variation of the microwave antenna having ahelical antenna portion.

FIG. 2Q shows the antenna variation from FIGS. 20 and 2P inserted intobreast tissue and surrounding a tumor.

FIG. 3A shows one variation for using multiple curved antennas which areadjacent to one another.

FIGS. 3B and 3C show isometric and end views, respectively, of anothervariation for using multiple curved antennas to form a cage-likeablation device.

FIG. 4 shows another variation for using multiple curved antennas inwhich the antennas approach the region of tissue from differentlocations and angles.

FIGS. 5A and 5B show isometric and end views, respectively, of anantenna having a single feedline with multiple antenna loops extendingtherefrom.

FIGS. 6A to 6C show side, top, and end views, respectively, of anantenna guide assembly variation which may be used to align microwaveantennas.

FIGS. 7A and 7B show isometric exploded and assembly views,respectively, of the guide assembly variation of FIGS. 6A to 6C.

FIGS. 8A and 8B show isometric and end views, respectively, of theantenna guide assembly of FIGS. 6A to 6C having microwave antennaspositioned within.

FIGS. 9A to 9C show side, top, and end views, respectively, of anothervariation of antenna guide assembly which may be used to align microwaveantennas.

FIGS. 10A and 10B show isometric exploded and assembly views,respectively, of the guide assembly variation of FIGS. 9A to 9C.

FIGS. 11A and 11B show isometric and end views, respectively, of theantenna guide assembly of FIGS. 9A to 9C having microwave antennaspositioned within.

FIGS. 12A to 12C show variations on different methods of attaching acurved microwave antenna.

FIGS. 13A to 13G show one variation on deploying and positioning acurved microwave antenna about a tissue region of interest.

FIGS. 14A and 14B show another variation on deploying the curvedmicrowave antenna about a tissue region of interest in which a wire andtube member may be deployed simultaneously.

FIG. 14C shows another variation on deploying the curved microwaveantenna about a tissue region of interest in which the inner conductorand dielectric coating may be deployed together as a single unit withinthe tissue.

FIGS. 15A and 15B show another variation on deploying the curvedmicrowave antenna about a tissue region of interest in which the tubemember may be used as an insulator during microwave treatment.

FIGS. 15C and 15D show another variation on deploying the curvedmicrowave antenna about a tissue region of interest in which the antennais partially assembled in situ prior to microwave treatment.

FIGS. 15E and 15F show another variation on deploying the curvedmicrowave antenna about a tissue region of interest where the innerconductor of the antenna is independently advanced through the tissue.

FIGS. 15G and 15H show one variation on a method for partiallyassembling the microwave antenna in situ.

FIGS. 16A to 16D show another variation on deploying the curvedmicrowave antenna about a tissue region of interest in which theintroducer may remain in place during antenna deployment.

FIGS. 17A to 17D show another variation on deploying the curvedmicrowave antenna using a backstop guide along which the antenna may beguided.

FIGS. 18A and 18B show cross-sectioned variations on the backstop ofFIGS. 17A to 17D.

FIGS. 19A to 19D show a variation on the microwave antenna which has anoptional RF energy cutting tip.

FIG. 19E shows a detailed view of one variation on the RF energy cuttingtip.

FIGS. 20A and 20B show schematic details of variations of combinedmicrowave and RF energy generators which may be used with the device ofFIGS. 19A to 19E.

FIG. 21 shows a schematic detail of a channel splitter assembly whichmay be used to create multiple channels by using a single source.

FIG. 22 shows a cross-sectional view of one variation for connecting themicrowave antenna assembly.

FIG. 23 shows a cross-sectional view of another variation for connectingthe microwave antenna assembly.

FIGS. 24A to 24C show alternative variations for connecting themicrowave antenna assembly using protrusions located on the feedline.

FIGS. 25A and 25B show an example of another possible application forthe microwave antenna in sealing aneurysms.

FIGS. 26A and 26B show another example of a possible application incoagulating malfunctioning valves in a vessel.

FIGS. 27A to 27D show another example of a possible application incoagulating fistulas formed between adjacent vessels.

FIGS. 28A and 28B show another example of a possible application intreating the soft core of a bone.

DETAILED DESCRIPTION OF THE INVENTION

Microwave ablation devices typically ablate the tissue surrounding theantenna. The present invention clearly defines an ablation region byhaving the microwave antenna surround at least a majority of the tissueto be ablated without the need to actually penetrate or contact theablated tissue. Furthermore, the curved microwave antenna allows for thedirect control over the outer extent of the thermal lesion created bythe device. FIG. 1A shows one variation in microwave antenna assembly 10which preferably comprises at least microwave antenna 12 electricallyconnected to generator 22. Microwave antenna 12 preferably comprisesshaft or feedline 14 with a distal end from which antenna or innerconductor 16 extends to define the ablation region 29, which isdescribed in detail below. The proximal end of feedline 14 preferablycomprises coupler 18 which electrically couples the antenna 12 togenerator 22 via power transmission cable 20. The cable 20 is preferablya flexible cable which allows for the positioning of antenna 12 relativeto a patient.

Feedline 14 is preferably a coaxial cable, as shown by the cross-section1B-1B in FIG. 1B taken from FIG. 1A. The feedline 14 may be formed ofouter conductor 24 surrounding inner conductor 26. Conductors 24, 26 maybe made of a conductive metal which may be semi-rigid or flexible. Mostfeedlines 14 may be constructed of copper, gold, or other conductivemetals with similar conductivity values. Alternatively, feedline 14 mayalso be made from stainless steel which may additionally be plated withother materials, e.g., other conductive materials, to improve theirproperties, e.g., to improve conductivity or decrease energy loss, etc.A feedline 14, such as one made of stainless steel, preferably has animpedance of about 50Ω and to improve its conductivity, the stainlesssteel may be coated with a layer of a conductive material such as copperor gold. Although stainless steel may not offer the same conductivity asother metals, it does offer strength required to puncture tissue and/orskin. A dielectric material 28 is preferably disposed between outer andinner conductors 24, 26, respectively, to provide insulationtherebetween and may be comprised of any appropriate variety ofconventional dielectric materials.

Furthermore, coaxial cables made from materials such as stainless steelmay result in higher energy losses than other conductive materials, e.g.copper, gold, silver, etc. FIGS. 1C and 1D show cross-sectional and endviews, respectively, of a variation of a feedline 14′ which hasconductive layers plated within to increase the energy transmission. Asshown, the outer surface of inner conductor 26 may be plated with atleast one additional conductive material described above in layer 27.Likewise, the inner surface of outer conductor 24 may be similarlyplated with layer 29, which may be made of the same, similar, ordifferent material as layer 27. The transmitted microwave energy istypically carried in the outer layers of inner conductor 26 so layer 27need not be relatively thick.

Moreover, the addition of conductive layers 26 and/or 27 may not onlyincrease energy transmission, but it may also aid in decreasing cablelosses, decreasing cable heating, and distributing the overalltemperature within the cable.

FIGS. 2A to 2G illustrate the different variations which the curvedmicrowave antenna may embody. The size of the curved antenna portion mayrange anywhere from several millimeters to several centimeters, e.g., a3 cm diameter or greater, depending upon the size of the tissue to betreated. The microwave antenna 12 may be used in various types oftissue, e.g., liver, breast, etc. In operation, microwave energy havinga wavelength, λ, is transmitted through microwave antenna 12 alongfeedline 14 and antenna 32. This energy is then radiated into thesurrounding medium, e.g., tissue. The length of the antenna forefficient radiation may be dependent at least on the effectivewavelength, λ_(eff), which is dependent upon the dielectric propertiesof the medium being radiated into. Energy from microwave antenna 12radiates and the surrounding medium is subsequently heated. A microwaveantenna 12 through which microwave energy is transmitted at awavelength, λ, may have differing effective wavelengths, λ_(eff),depending upon the surrounding medium, e.g., liver tissue, as opposedto, e.g., breast tissue. Accordingly, to optimize the efficiency atwhich energy is radiated into the surrounding tissue, antenna length 32may be varied to match according to the type of tissue surrounding theantenna. Also affecting the effective wavelength, λ_(eff), are coatingsand other structures, e.g., inflatable balloons, which may be disposedover microwave antenna 12, as discussed further below.

Curved antenna 32 is seen in FIG. 2A extending from feedline 14 fromfeedline terminal end 30. Curved antenna 32 may either be attached toinner conductor 26, which is within feedline 14, through a variety ofattachment methods (as described below) or antenna 32 may simply be anintegral extension of inner conductor 26. Various conductive materialsmay be used to fabricate antenna 32, as above, and it may also befabricated from shape memory alloys such as Nitinol. Alternatively, if ametal such as stainless steel is used, it may be biased to form thearcuate or curved shape as shown in the figures. Additionally, to helpprevent energy from being conducted directly into contacting tissue, adielectric coating may be placed over at least a majority of curvedantenna 32. This coating may also aid in increasing the amount ofradiated energy from antenna 32. Moreover, the coating is preferablylubricious to aid the insertion of antenna 32 into tissue as well as toaid in preventing tissue from sticking to antenna 32. The coating itselfmay be made from various conventional materials, e.g., polymers, etc.

The curved antenna 32 portion is preferably curved to form a loop orenclosure which is selectively formed large enough for surrounding aregion of tissue, e.g., a lesion or tumor, to be radiated within thepatient without making any contact with the tissue. Because no contactoccurs between antenna 32 and the tumor, any danger of dragging orpulling cancerous cells along the antenna body into other parts of thebody during insertion, treatment of the tissue, or removal of theantenna is eliminated. When microwave energy is delivered throughfeedline 14, curved antenna 32 and any part of the feedline or antenna32 that completes the enclosure becomes part of the radiating portion.However, rather than radiating directly along the length of curvedantenna 32, as one skilled in the art would normally expect, the curvedconfiguration forms an ablation field or region 35 defined by curvedantenna 32 and any tissue enclosed within ablation region 35 becomesirradiated by the microwave energy. Thus, because of the variability ofantenna 32 and ablation region 35, the microwave antenna may be used totreat a variety of tissue size ranges and is not constrained by antennadelivery or deployment mechanisms. Any concurrent thermal effects mayextend beyond the ablation region 35 outside curved antenna 32 by ashort distance, e.g., a few millimeters to several millimeters.Accordingly, curved antenna 32 also defines a predictable region oftissue outside the irradiated zone which will also be irradiated. Thismargin 33 of tissue is generally very predictable and serves to treatthe tissue the short distance outside the ablation region to ensurecomplete treatment of the area.

As previously mentioned, curved antenna 32 may be formed into a varietyof shapes so long as antenna 32 preferably forms a substantiallyenclosed loop or enclosure, i.e., curved antenna 32 surrounds at least amajority of the tissue to be enclosed. Accordingly, antenna 32 may beformed into shapes such as circles, ellipses, spirals, helixes, squares,rectangles, triangles, etc., various other polygonal shapes, and partialforms of the various shapes so long as a majority of the enclosed tissueis surrounded. FIG. 2A shows antenna 32 formed into a complete loop inwhich distal tip 34 loops around to contact a proximal region of antenna32 while clearly defining ablation region 35. The contact point betweenthe two is preferably insulated such that no direct metal-to-metalcontact occurs.

Another variation is shown in FIG. 2B in which distal tip 38 of curvedantenna 36 is looped greater than 360° relative to feedline terminal end30. The curved antenna may be looped or wound about the selected tissueregion from about 180° (relative to a central point defined by thecurved antenna), where the tissue is just surrounded or partiallyenclosed by the antenna, to multiple loops where the tissue issurrounded numerous times by the antenna. Separation between theindividual loops is shown for clarity and is not intended to be limitingsince contact between the loops may occur. The number of times which thetissue is surrounded may be correlated to the desired radiation effects,as discussed in further detail below.

FIG. 2C shows another variation in which distal tip 42 of curved antenna40 is wound greater than 360° relative to feedline terminal end 30 butwhere antenna 40 is formed into a more elliptical shape. In thisvariation, antenna 40 forms overlapping region 31 with a distal portionof feedline 14. In such an overlapping area, overlap region 31 offeedline 14 may form part of antenna 40. FIGS. 2D to 2F show the distaltips 46, 50, 54 of each of curved antennas 44, 48, 52, respectively,with various degrees of enclosure. Although numerous different shapesand partial shapes may be utilized, the enclosure is preferably formedin a looped configuration with at least a partial overlap between thedistal tip and either a portion of the feedline 14 or with the antennaitself. If the overlap is formed with feedline 14, as shown in FIG. 2D,a portion of feedline 14 itself may act as part of the antenna 44 whenpower is applied. If a separation exists between distal tip 50 andfeedline terminal end 30, as shown in FIG. 2E, then a distance, d,between the two is preferably less than 3 cm, and more preferably lessthan 1 cm such that an ablation region is clearly defined by theantenna. Accordingly, feedline 14 over the distance, d, may form part ofthe radiating antenna 48 in such a configuration. Otherwise, variousother shapes or partial shapes may be utilized.

An alternative variation is shown in FIG. 2G where feedline 56 isextended into a curved portion 58 to partially define the ablationregion. Curved antenna 60 may be used to complete the enclosure. Curvedportion 58 is shown forming an arc of about 180°, but it may be formedinto any curved portion with varying degrees of curvature to partiallyform the ablation region.

An optional method for optimizing the length of the antenna to thetarget tissue site may involve adjusting the length of the antennaitself to optimize the amount of microwave energy which is delivered tospecific tissue types such that the effective wavelength, λ_(eff), ismatched to the surrounding tissue medium type. For instance, dependingupon the tissue type, the microwave antenna may be shortened in lengthto increase the frequency with which the energy is deliveredefficiently. Alternatively, antenna length may also be shortened todecrease the frequency as certain frequencies are more efficient atdelivering energy in certain tissue types.

Shorter antenna lengths may easily be inserted within the matchingtissue type with relative ease; however, longer antenna lengths maypresent a challenge in deployment and placement within the tissue. Onemethod of adjusting for antenna length is seen in the variation shown inFIG. 2H. Curved antenna 61 extends from feedline 14, as in othervariations, but has an additional distal portion 63 which doubles backaround curved antenna 61 from tip 62. Distal antenna portion 63 may liewithin the same plane as curved antenna 61 or it may optionally bepositioned at an angle relative to antenna 61. In either case, tip 62may be configured to have a cutting edge to facilitate insertion intothe tissue, or it may also be optionally configured to provide an RFenergy cutting tip, which is described in greater detail below.

While distal antenna portion 63 is shown in FIG. 2H as doubling backalong nearly the entire length of curved antenna 61, it may be sized toany practical length to match the tissue type. For instance, FIG. 2Ishows a variation in which distal antenna portion 64 extends back fromtip 62 only partially along the length of curved antenna 61. Anothervariation is shown in FIG. 2J in which curved antenna 65 has a loopedportion 66 extending partially along the length of curved antenna 65.Looped portion 66 may be any appropriate length of antenna which issimply formed into a looped or coiled structure. The portion 66 may alsobe located anywhere along the length of curved antenna 65.

Additional variations are shown in FIGS. 2K and 2L in which any numberof double-back portions of the antenna may be formed. FIG. 2K showscurved antenna 67 with two doubled portions 68 along its length. Thisvariation is not limited by the number of doubled portions but mayinclude any number as necessary to achieve the desired radiative andgeometric effects. FIG. 2L shows another variation in which curvedantenna 69 has a distal portion 71 doubling back along antenna 69, andwhich also has an additional proximal portion 73 formed in another planerelative to the plane formed by antenna 69.

FIG. 2M shows a variation which is similar to that shown in FIG. 2J butin which the antenna is formed entirely into a looped or coiled antenna75. The coiled antenna 75 may have a coil diameter which is uniformalong the length of antenna 75 or it may optionally have a variable coildiameter along its length. The coiled antenna 75 allows for a microwaveantenna having a relatively large antenna length constrained within anarea no larger than some of the other variations described herein.

As discussed above, the effective wavelength, λ_(eff), of the microwaveradiation may also be affected, aside from antenna length, by coatingsand other structures which may be disposed over the microwave antenna.Accordingly, a layer of insulative material may be varied in thicknessover at least a majority of the length of the curved antenna to achievea matched effective wavelength. Alternatively, an inflatable balloon 77may be disposed over the length of curved antenna 52, as shown in FIG.2N to also match the effective wavelength. Balloon 77 may be in adeflated state during the deployment of antenna 52 within the tissue.Once antenna 52 has been desirably positioned, balloon 77 may be filledwith a liquid, e.g., saline, water, etc., until it has inflatedsufficiently about antenna 52. The size of balloon 77 may be variedaccording to the desired radiative effects, the length of antenna 52, aswell as the type of tissue which the antenna 52 will be inserted within.

As described above, an antenna may be looped about the region of tissueto be ablated any number of times. The multiple coils or loops may allbe wound within the same plane or alternatively, they may be wound in aspiral or helical configuration. FIGS. 2O to 2Q show a variation inwhich a helically configured antenna 80 may comprise a straightenedportion or feedline 81 and a helical portion 88 which is insertablewithin the tissue. FIG. 2O shows a top view of a variation on theantenna 80 which is similar in configuration to the device shown anddescribed in U.S. Pat. No. 5,221,269 to Miller et al., which has beenincorporated above by reference in its entirety. As seen in thisvariation, helical portion 88 comprises antenna 83 which is configuredinto a tapering helical pattern to form an ablation region 85 within thehelical portion 88, as better shown in the cross-section 2P-2P in FIG.2P. Antenna 83 may terminate in a tapered distal tip 84 to facilitateantenna entry into the tissue. Helical portion 88 may alternatively beformed into a coiled section in which multiple coils are formed with auniform diameter. The number of coils antenna 83 forms may be determinedby the optimal antenna length desired according to the tissue type beingtreated, as described above in detail.

As seen in FIG. 2Q, antenna 83 is shown as having been inserted intobreast 87 to treat tumor 86. Antenna 83 may be inserted within breast 87in an uncoiled and straightened configuration through an introducer (notshown). Antenna 83 is preferably made from a shape memory alloy, e.g.,Nitinol or some other similar alloy, such that as distal tip 84 isinserted within the tissue, it may be preconfigured to form the helicalshape as antenna 83 is further inserted within the tissue. As antenna 83is advanced, distal tip 84 may form the helical shape about the tumor86, or some region of tissue to be ablated, within the formed ablationregion 85.

To ablate larger regions of tissue, multiple microwave antennas may beused in conjunction with one another. FIG. 3A shows two antennas, firstfeedline 70 and second feedline 70′, positioned adjacent to one anothersuch that their respective antennas, first antenna 72 and second antenna72′, are positioned to ablate a larger region of tissue over a distancewithin their combined ablation regions 74. Another variation using twoantennas is shown in FIGS. 3B and 3C in which first and second feedlines70, 70′ are positioned adjacent to one another with their respectiveantenna portions 72, 72′ being positioned to interloop with one another.FIG. 3C shows an end view of FIG. 3B in which the interlooped antennas72, 72′ may be seen to form ablation region 74 within the combined areasof the antennas. The caged ablation region 74 is effective in completelyencapsulating a region of tissue to be ablated within a sphericalablation region. Other shapes, e.g., spheroid, ovoid, ellipsoid, etc.,may alternatively be formed by a combination of the two antennas 72, 72′positioned appropriately or any number of antennas as practical ordesired.

Alternatively, first and second feedlines 70, 70′ may be positioned toapproach the region of tissue to be ablated from different locations andat different angles, as seen in FIG. 4, such that the combined effect ofthe first and second antennas 72, 72′ may form a complete loop or shapeand ensures complete coverage of the ablation region 76. In either ofthese variations, any number of antennas may be used as practicabledepending upon the size of the tissue to be ablated as well as thedesired effect from the ablation.

Alternatively, a single feedline 78 having multiple antennas 80 whichdefine an ablation region 82 over some distance may be utilized, as seenin the FIG. 5A. In this variation, a plurality of antennas, i.e., two ormore, may extend from a single feedline 78 to form an enlarged ablationregion. Because a single feedline is used, a single incision in apatient is required while a relatively large area of tissue may beablated with the single device. FIG. 5B shows an end view of thevariation from FIG. 5A and shows the multiple antennas 80 extending fromthe single feedline 78. Multiple antennas 80 may be positioned in anyvariety of configurations relative to one another depending upon theareas of tissue to be ablated.

Alternative embodiments which may be utilized for forming caged ablationregions using multiple antennas may be seen in PCT publication WO01/60235 to Fogarty et al. entitled “Improved Device for AccuratelyMarking Tissue”, which is incorporated herein by reference in itsentirety. Similarly, multiple antennas may be used to form cagedembodiments for surrounding tissue within an ablation region usingconfigurations similar to the tissue marking devices described in thepublication.

To assist in aligning multiple antennas for ablating larger regions oftissue, various alignment guides may be used to provide for uniform orconsistent antenna placement within the tissue to be treated. Onevariation may be seen in FIGS. 6A to 6C which shows side, top, and endviews, respectively, of antenna guide assembly 180. Guide assembly 180may be used to align microwave antennas parallel to each other in onevariation as shown in FIG. 3A. In use, a distal end of a microwaveantenna may be advanced through proximal entry 186 of guide assembly180, through guide passage 184 and out through distal port 188 such thata portion of the microwave antenna extends beyond distal port 188 forinsertion into the tissue region to be treated. The antenna may bereleasably locked into position within guide assembly 180 by lockingassembly 190.

The guide assembly 180 itself may be comprised of guide body 182, whichmay be made as an integral unit from a variety of materials, e.g.,various polymers or plastics, etc. Guide body 182 may have an outersurface configured to be held by a surgeon or physician. Within theguide body 182, one or more guide passages 184 may be defined throughthe length of guide body 182 for holding and aligning the microwaveantennas. Although this variation shows two passages 184 for aligningtwo antennas, this is merely illustrative and other variations may beemployed for aligning any number of antennas as practicable, e.g., asingle antenna or three or more.

As further shown, guide body 182 also defines proximal entry 186 throughwhich the antennas may be advanced into passages 184 and through distalports 188. The antennas may be further positioned through lockingassembly 190 located within guide body 182 and used to temporarily lockthe antennas in place. The antennas may be locked within assembly 190 bylocking mechanism 192 which may be keyed to lock against the antenna. Torelease a locked antenna, locking assembly 190 may further have releaselatches 194 which are configured to release locking mechanism 192 torelease the antenna. Locking assembly 190 may be held in place withinguide body 182 by retaining members 196, which may be configured asthreaded or snap-fit members for engagingly attaching onto a portion oflocking assembly 190.

To align the microwave antennas with guide assembly 180, guide body 182may define longitudinal alignment channels 198 along the lengths of eachguide passage 184. Alignment channels 198 may extend through guide body182 from guide passages 194 to the outer surface of guide body 182 andthey may be aligned parallel to each other along the length of guideassembly 180, as shown in FIG. 6B. The microwave antennas used withguide assembly 180 may be configured to have a corresponding protrusion(not shown) extending from the feedline body and the protrusion may bekeyed to align with and travel through alignment channels 198. It is thealignment of the keyed antenna with the alignment channels 198 which mayforce the antennas to desirably align with each other such that thelooped antennas extend parallel to one another.

FIGS. 7A and 7B show isometric exploded and assembly views,respectively, of guide assembly 180. The exploded view in FIG. 7A showsrelease latches 194 aligned with locking mechanism 192. Latches 194 maybe aligned and held in position with pins 200 relative to mechanism 192.Ferrules 202 may also be used for placement within locking mechanism 192to facilitate antenna alignment.

FIGS. 8A and 8B show isometric and end views, respectively, of antennaand guide assembly 210. First 212 and second 212′ antenna feedlines areshown in this variation as having been positioned within guide body 182such that first 214 and second 214′ looped antennas are parallel to oneanother. As shown in FIG. 8B, antennas 214, 214′ may be positioned andmaintained in this parallel manner for treatment of regions withintissue. Although shown in this variation as having parallel antennas,the possible orientations of the antennas are not so limited. Otherrelative positions for the antennas may be utilized depending upon thedesired effects.

Another variation for facilitating antenna positioning is shown in FIGS.9A to 9C. In this variation, antenna guide assembly 220 similarly hasguide body 222 with guide passages 224 defined throughout the assembly220 and ending in distal port 232 through which microwave antennas maybe positioned. Locking assembly 226 may also similarly comprise lockingmechanism 228 for temporarily locking the antennas into position.Locking mechanism 228 is located within guide body 222 and held theretovia retaining members 236, which may be any of the retaining members asdescribed above. Release latch 230 may be used to release lockingmechanism 228 for releasing locked antennas. This variation 220,however, may be used when the antennas are desirably angled relative toone another, similar to the antenna placement variation shown in FIGS.3B and 3C. Accordingly, alignment channels 234 may be formed withinguide body 222 such that the channels 234 are angled away relative toeach other.

As shown in FIGS. 10A and 10B, which are isometric exploded and assemblyviews, respectively, of guide assembly 220, alignment channels 234 maybe angled relative to one another such that they are angled away. Bothor either channel 234 may be angled at various angles, α, depending uponthe desired antenna positioning, e.g., 30°, 45°, etc. Alternatively,they may be angled towards one another as practicable.

FIGS. 11A and 11B show isometric and end views, respectively, of antennaand guide assembly 240. The antennas used with this guide variation mayalso be configured to have protrusions such that they are keyed to alignwithin the channels 234 at specified angles. For instance, as shown inFIG. 11A, first 242 and second 242′ feedlines may be positioned throughguide body 234 such that first 244 and second 244′ antennas areinterlooped with one another to form an enclosed ablation region, asdescribed above. Depending upon the angle at which either or bothantennas 244, 244′ are positioned relative to one another, a variety ofshapes may be formed by the antennas, as further discussed above.

As further mentioned above, the curved antenna may either be attached tothe inner conductor, which is disposed within the feedline, throughvarious attachment methods or the antenna may simply be an integralextension of the inner conductor. FIG. 12A shows a cross-sectioned sideview of the terminal end of feedline 14. As seen, outer conductor 24surrounds inner conductor 90 and is separated by dielectric 28. Thepoint where inner conductor 90 begins to form the curved antenna, outerconductor 24 and dielectric 28 end while inner conductor 90 continues onto form an integrally attached antenna.

An alternative variation is seen in FIG. 12B in which a separate antenna94 is mechanically affixed or attached to inner conductor 92, which mayextend partially from outer conductor 24. The mechanical connectionbetween antenna 94 and inner conductor 92 may be accomplished by avariety of methods, only a few of which are described herein. Connector96 may be used to electrically and mechanically join each of theterminal ends of inner conductor 92 to antenna 94 through connectorlumen 98, e.g., by a simple mechanical joint, or by soldering both endstogether and additionally soldering connector 96 over the joint. Asidefrom solder, a conductive adhesive may similarly be used. Alternatively,each of the terminal ends may be crimped together by connector 96.

Another variation may have each of the terminal ends threaded inopposite directions so that inner conductor 92 may be screwed intoconnection with antenna 94 via a threaded connector lumen 98. If aseparate antenna is utilized, then one made from the same material asinner conductor 92 may be used. Alternatively, an antenna 94 made from ashape memory alloy, e.g., Ni—Ti alloy (Nitinol), may be attached.However, any oxide layers which may form on the surface of the shapememory alloy is preferably removed by using, e.g., a reamer, prior toattachment. An alternative attachment which may be utilized is shown inFIG. 12C in which a tubular antenna 100 having an antenna lumen 102 maybe attached to inner conductor 92 by partially inserting the conductor92 within lumen 102 prior to mechanical fixation. The tubular antenna100 may then be similarly attached to inner conductor 92 using thevarious methods described above, e.g., soldering, crimping, adhesives,etc.

Insertion and placement of the microwave antenna within the body of apatient may be accomplished through one of several different methods.One method is shown in FIGS. 13A to 13G, which show the deployment andplacement of a microwave antenna about a region of tissue to be ablated.Once a region of diseased tissue, e.g., a tumor, has been located withina patient's body, e.g., within the breast or the liver, a microwaveantenna may be deployed in vivo to effect treatment. As seen in FIG.13A, introducer 114 may be inserted through skin surface 112 in an areaadjacent to the tumor 110. Wire 116, which may be held within introducer114 during insertion or inserted afterwards, may then be advancedthrough introducer 114 and through the tissue surrounding tumor 110.Wire 116 is preferably made of a shape memory alloy which is preformedto have a curvature in any of the shapes described herein, although itis shown in the figure as a circular loop. This curvature is selectivelypreformed such that wire 116 is able to at least substantially surroundtumor 110 while being advanced without contacting the exterior of tumor110.

Once wire 116 has been desirably positioned around tumor 110, introducer114 may be removed from the tissue area while maintaining the positionof wire 116, as shown in FIG. 13C. Then, as shown in FIG. 13D, aflexible guide tube 118 may be advanced over wire 116 preferably all theway to the distal tip of wire 116. Once tube 118 has been positioned,wire 116 may then be withdrawn, as seen in FIG. 13E, and microwaveantenna 12 may be advanced within tube 118 such that antenna 16substantially surrounds tumor 110, as seen in FIG. 13F. Then tube 118may be withdrawn from the area while maintaining the position ofmicrowave antenna 12 about tumor 110 for treatment to be effectuated, asseen in FIG. 13G.

An alternative method of deployment is shown in FIGS. 14A and 14B.Introducer 114 may be positioned as above, but wire 116 and tube 118 maybe deployed simultaneously rather than sequentially, as seen in FIG.14A. Once the two have been desirably positioned, wire 116 may bewithdrawn from tube 118, as shown in FIG. 14B, and the microwave antenna12 may be inserted and positioned as above.

Another variation for deployment is shown in FIG. 14C where onceintroducer 114 has been positioned through skin surface 112, or someother tissue interface, inner conductor 117 surrounded by dielectric 115may be advanced together through the tissue to enclose tumor 110 withinan ablation region. As such, inner conductor 117 and dielectric 115 maybe integrally formed into a single unit; alternatively, inner conductor117 may be slidably disposed within dielectric 115 but advancedsimultaneously. The introducer 114 in this variation may be adapted tobe used as an outer conductor during microwave energy transmissionthrough the device.

Another variation for deployment and use of the microwave antenna 12 isshown in FIGS. 15A and 15B. Microwave antenna 12 may be positionedwithin tube 118, as above and as in FIG. 15A. However, rather thanwithdrawing tube 118 entirely from the tissue, it may be partiallywithdrawn until it covers only the feedline of microwave antenna 12 suchthat it may be used as an insulator between the shaft or feedline andthe surrounding tissue, as shown in FIG. 15B.

A similar variation may be seen FIGS. 15C and 15D. In this variation,the inner conductor portion with antenna 16 extending therefrom and thesurrounding dielectric 28 may be formed without an outer conductorsurrounding dielectric 28. Introducer 114 may be used as the outerconductor in constructing the microwave antenna in situ prior totreating the tissue. FIG. 15C shows introducer 114 having beenpositioned within the tissue adjacent to tumor 110. Antenna 16 anddielectric 28 may be advanced within introducer 114 until dielectric 28is preferably at the distal end of introducer 114 within the tissue.With antenna 16 surrounding tumor 110 and dielectric 28 properlypositioned within introducer 114, ablation of the tissue may be effectedwith introducer 114 acting as the outer conductor for the microwaveantenna.

Another alternative is shown in FIGS. 15E and 15F in which introducer114 and dielectric 28 may be first positioned within the tissue. Oncethey have been desirably positioned, antenna 16 (inner conductor) may beadvanced independently through both dielectric 28 and introducer 114 forplacement around tumor 110, as shown in FIG. 15F.

FIGS. 15G and 15H show one variation which allows a microwave antenna tobe assembled in situ within the tissue, as described above. Onceintroducer 114 has been positioned within the tissue, dielectric 28 andantenna 16 may be advanced within introducer 114 from proximal end 119of introducer 114. Alternatively, they may already be disposed withinthe introducer 114 during placement within the tissue. In either case,coupler 18 leading to the generator may be electrically connected toantenna 16 at its proximal end and coupler 18 may be advanced distallyinto mechanical attachment with proximal end 119 such that dielectric 28and antenna 16 are advanced distally out of introducer 114 and into thetissue. The mechanical attachment between coupler 18 and proximal end119 may be accomplished by any variety of mechanical fastening methods,e.g., crimping, adhesives, threaded ends, friction fitting, etc. Otherexamples of antennas which may be assembled in situ are described infurther detail in U.S. Pat. Nos. 6,306,132 and 6,355,033 (both toMoorman et al.), each of which is incorporated herein by reference intheir entirety. Techniques and apparatus as disclosed in these patentsmay be utilized in the present invention as examples of assembling themicrowave antennas.

Yet another variation for the deployment is shown in FIGS. 16A to 16D.FIGS. 16A and 16B show the insertion and positioning of introducer 114and wire 116 adjacent to tumor 110, as described above. However, ratherthan withdrawing introducer 114 from the tissue, it may be maintained inposition while tube 118 is advanced over wire 116 to provide strength totube 118 as it is advanced over wire 116 through the tissue, as seen inFIG. 16C. FIG. 16D shows wire 116 having been withdrawn from tube 118and microwave antenna 12 having been advanced through tube 118 whileintroducer 114 is maintained in position. The operation of microwaveantenna 12 may subsequently be accomplished with or without the presenceof introducer 114.

Another variation on the deployment of the microwave antenna is shown inFIGS. 17A to 17D. In this variation, a backstop guide 120 may beutilized rather than a wire 116 or tube 118. Backstop guide 120 is aguide which is preferably configured to define a channel along thelength of the backstop 120 within which a microwave antenna 12 may beadvanced through or along for positioning antenna 16 about tumor 110.Backstop 120 is preferably made from a shape memory alloy, e.g.,Nitinol, which is preconfigured to assume a looped or curved shape forpositioning itself about a region of tissue. Variations on thecross-section of backstop guide 120 are shown in FIGS. 18A and 18B. FIG.17A shows backstop 120 being advanced through skin 112 adjacent to tumor110. As backstop 120 is further advanced, it preferably reconfiguresitself to surround the tissue region to be ablated, e.g., tumor 110, asseen in FIG. 17B. Once backstop 120 has been desirably positioned,microwave antenna 12 may be advanced along backstop 120 as antenna 16follows the curve defined by backstop 120 around tumor 110, as seen inFIG. 17C. Finally, once microwave antenna 12 has been positioned,backstop 120 may be withdrawn from the tissue area, as seen in FIG. 17D,so that treatment may be effected.

FIGS. 18A and 18B show cross-section variations of backstop 120. FIG.18A shows one variation where backstop 120′ has a channel 122 which hasa rectangular configuration and FIG. 18B shows another variation inwhich backstop 120″ has a channel 124 having a rounded channel. When themicrowave antenna 12 is deployed using the backstop 120, antenna 16 ispreferably guided during deployment through the tissue by traversingwithin or along channels 122 or 124. Although only two variations on thebackstop cross-section are shown, other shapes for the backstop andchannel may be utilized and is not intended to be limiting.

A microwave antenna may be deployed either using an introducer and tube,as described above, or it may be inserted directly into the tissue tosurround or enclose the tissue region of interest. In either case,during deployment the antenna may encounter resistance from some areasof tissue, particularly in some tissue found, e.g., in the breast. Whenthe microwave antenna encounters resistance, the antenna may simply bepushed through by applying additional force; however, there could be apotential for buckling of the antenna and unnecessary tissue damage.Thus, RF energy may also be utilized with the microwave antenna forfacilitating deployment within the tissue. One variation comprisesapplying RF energy at the distal tip of the antenna as a cuttingmechanism during antenna deployment. The microwave antenna is preferablyinsulated along most of its length, but the distal tip may beuninsulated such that the RF energy may be applied thereto. To utilizethe RF energy cutting mechanism at the distal tip, the antenna may bemade from Nitinol or other metal. Alternatively, if the tubular antennavariation 100 from FIG. 12C is utilized, a metallic wire may be routedthrough antenna lumen 102 to the distal tip so that the wire may be usedas the RF cutting tip. This wire would be connected to a generator whichmay supply both the RF and microwave energy. The metallic wire may bemade of, e.g., Tungsten or some other appropriate conductive material.

An example of using the RF cutting tip is shown in FIGS. 19A to 19D.After introducer 114 has been positioned adjacent to tumor 110, feedline130 and antenna 132 may be advanced therethrough. Cutting tip 134 maysimply be pushed forward through tissue so long as no resistance isencountered, as shown in FIGS. 19A and 19B. Once resistance from thetissue is encountered, RF energy may be supplied to antenna 132 toactivate cutting tip 134, as seen in FIG. 19C. With the RF energy on,antenna 132 may be further advanced, as seen in FIG. 19D, while cuttingtip 134 cuts through the obstructive tissue. The RF energy may simply beleft on the entire time antenna 132 is advanced through the tissue, orit may be applied or turned on only as needed as cutting tip 134encounters resistance from the tissue. Once antenna 132 has beendesirably positioned about tumor 110, the RF energy, if turned on, maybe switched off and the microwave energy may be switched on to effecttreatment within the newly created ablation region 136.

FIG. 19E shows a detailed view of one variation of cutting tip 134. Asshown, antenna 132 may comprise an inner conductor which is preferablycovered by insulation 138. To effect the cutting mechanism, distal tipportion 140 may be exposed such that when RF energy is supplied toantenna 132, the exposed tip portion 140 may be utilized to heat and cutthrough the tissue directly encountered by tip portion 140. The distaltip portion may optionally be tapered or appropriately shaped, such asin a trocar configuration, to further enhance the cutting tip.

Given the small amount of surface area of tip portion 140, a low powerRF generator may be utilized and can be built into an integral unitalong with the microwave generator. Alternatively, the optional RFgenerator may be physically separated from the microwave generator andmay be electrically connected as a separate unit. FIG. 20A schematicallyshows a variation on generator unit 150 which combines microwavegenerator module 154 with RF generator module 156 into a single unit150. Both modules 154, 156 may be supplied by a single power supply 152also contained within unit 150. Power supply lines 158 may electricallyconnect the modules 154, 156 to power supply 152. A separate line 160(e.g., cable) may connect microwave module 154 to microwave antenna 132and another line 162 may connect RF module 156 to cutting tip 134.Alternatively, the separate lines 160, 162 may be connected into asingle line 164 which is electrically connected to both antenna 132 andcutting tip 134 to alternately supply the power for both the microwaveand RF energy through the singular connection.

FIG. 20B shows another variation on generator unit 150 in which separatelines 160, 162 are connected into a single output 165, which may beconnected to antenna 132 and cutting tip 134. Also shown are optionalswitches 166 and 168, which may be connected to microwave and RF modules154, 156 via lines 167, 169, respectively. Switches 166, 168 may beoptionally utilized to enable the surgeon or physician to select thedesired output from either or both modules 154, 156 at any time.Switches 166, 168 may accordingly be separate switches or combined-intoa single unit located remotely from generator unit 150. Furthermore,they may be made in one variation as hand-operated switches or inanother variation as foot-operated switches or any variety of actuationswitches as may be known in the art.

In addition to utilizing integrally combined RF and microwavegenerators, another variation which may be utilized involves creatingmultiple channels from a single unit by multiplexing and cycling theoutput. This is particularly useful when using multiple microwaveantennas, as shown in FIGS. 3 and 4, since the effects of multiplechannel generators, which typically requires the use of multiplegenerators, are accomplished by using a single generator and results ina much lower power consumption. For instance, a three channel 100 Wgenerator system would require about three times the power, i.e., 300 W,as used by a single channel system if the power were produced for eachchannel simultaneously.

Accordingly, FIG. 21 schematically shows channel splitter assembly 170which may be used to create multiple channels by using a single sourcewith multiplexing. A single microwave generator module 154 having, e.g.,a 100 W output, may create a single channel A. The single channel A maybe switched between several separate channel outputs A₁ to A_(N) createdby channel splitter 172. Any number of multiple outputs may be useddepending upon the desired number of channels and the desired effects.In use, the output may be cycled through the range of outputs 176through multiple channels A₁ to A_(N) or in any other manner dependingupon the lesion to be created. Moreover, the rate of cycling may rangeanywhere from several microseconds to several seconds over a treatmentperiod of several minutes or longer.

Controller 174, which is preferably in electrical communication withchannel splitter 172 may be used for several purposes. It may be used tocontrol the cycling rate as well as the order of channels in which theoutput is cycled through. Moreover, controller 174 may be an automaticsystem or set by the technician or physician. An automatic system may beconfigured to detect the electrical connection to the antenna and tocontrol the delivery of the energy to the antenna. The detection may beachieved by either a passive or active component in the system which maymonitor reflections from the antenna to determine whether a properconnection is present. A controller set by the technician or physicianmay be configured to require manual initiation for energy delivery tobegin.

Additional features which may be utilized for the microwave antennas mayinclude certain safety features. For instance, a connection mechanismmay allow for antenna connection with an outer shell of a conventionalor custom connector. It may be configured such that an electricalconnection may be achieved upon full deployment of the inner conductorcurved antenna such that no electrical connection is maintained duringdeployment. Such a feature could allow an operator to safely assembleand deploy the device without premature microwave antenna activation.

FIG. 22 shows a cross-sectional view of one variation for connectingmicrowave antenna assembly 300. In this variation, connector shell 302may extend from connector 304 and attach to a proximal end of feedline306. Inner conductor 308 may extend throughout the length of theassembly 300 from pin 310, which may connect to a cable leading to amicrowave power generator, and end in curved antenna 312 for deploymentwithin the tissue. The connector shell may contain a feedline, as shownin FIG. 22. To advance curved antenna 312 from within feedline 306 intotissue, receiving connector end 316 of connector shell 302 may beadvanced into contact with proximal end 314 of feedline 306. Asconnector end 316 comes into physical contact with proximal end 314,curved antenna 312 may be advanced out of feedline 306 and into thetissue. Also, retaining member 318, which may simply be a protrusion orother fastener as known in the art, may provide a secure contact betweenconnector shell 302 and feedline 306. Furthermore, retaining member 318may be an electrically conductive contact such that it also provides asecure electrical communication path between connector shell 302 andfeedline 306 to allow for the microwave energy to be transmitted betweenthe two. This feature may also act as a safety feature in that curvedantenna 312 is preferably fully deployed out of feedline 306 before theelectrical connection is made between feedline 306 and connector shell302.

FIG. 23 shows a cross-sectional view of another variation for connectingmicrowave antenna assembly 320. This variation 320 shows connector shell322 which may be shortened from the previous variation 300. As shown,proximal end 328 of feedline 326 may receivingly extend into connectorshell 322 and into contact with retaining member 330, which may beconfigured similarly as above. Inner conductor 332 may extend throughassembly 320 from pin 336 within connector 324 to curved antenna 334. Asfeedline 326 is placed into secure electrical contact with connectorshell 322 via retaining member 330, curved antenna 324 may be advanceddistally out of feedline 326.

In addition to or in place of the retaining members described above,protrusions may instead be placed on an outer surface of the antennafeedline. As shown in FIG. 24A, one variation may be seen in antennaassembly 340. Connector 342 may be seen prior to connection with aproximal end of feedline 344. Inner conductor 346 is shown extendingthrough connector 342 and feedline 344, while plating layer 348 may beseen upon an outer surface of feedline 344. Layer 348 may be made from aconductive material, e.g., solder, or other conductive metal. FIG. 24Bshows another variation in antenna assembly 350 which has a layer ofplating 352 having tapered edges to facilitate insertion of feedline 344within connector 342. FIG. 24C shows yet another variation in antennaassembly 354 in which multiple separate layers 356 of plating may beutilized. These variations are merely illustrative and any number ofother various configurations may be utilized depending upon the desiredresults.

Any of the antenna variations and methods for use and deploymentdescribed herein may be utilized in a variety of medical treatmentsaside from tumor ablation. For example, a curved microwave antenna beused to seal an aneurysm 360 extending from a body vessel 364, as seenin FIG. 25A. In such use, the surgeon or physician may inject a contrastagent into the patient's circulatory system. Then, with the assistanceof an X-ray imager, e.g., a fluoroscope, the surgeon may locate theaneurysm 360. Introducer 366 of the antenna device may be inserted intothe tissue and the tip of introducer 366 may be placed adjacent to neck362 of aneurysm 360. Curved antenna 368 may be deployed around neck 362of aneurysm 360, as seen in FIG. 25B. Microwave energy may be directedthrough curved antenna 368 to ablate neck 362 located within theablation region. Curved antenna 368 may then be retracted back intointroducer 366 and the device may be then withdrawn from the subject'sbody.

In another example of application, curved antenna 368 may be utilized toocclude vessel 370 as shown in FIG. 26A. As shown, curved antenna 368may be deployed around the tissue of interest, in this case vessel 370instead of the neck of an aneurysm. The vessel 370 in this example has amalfunctioning valve 372. Microwave energy may be directed throughcurved antenna 368 and into vessel 370, which is positioned within theablation region of antenna 368, to induce a coagulated region 374 ofblood to halt the flow of blood in the vessel 370, as shown in FIG. 26B.

In yet another example, the microwave antenna may be used to treat afistula. As shown in FIG. 27A, in a normal condition, e.g., an artery380 and, e.g., a vein 382, are located adjacent to each other andtypically have blood flow that is isolated from each other. Anabnormality known as a fistula 384 may permit the passage of blood flowfrom, e.g., an artery 380 to a vein 382, as shown in FIG. 27B. Curvedmicrowave antenna 368 may be used to seal the fistula 384 between thetwo blood vessels 380, 382 using methods similarly described above, asshown in FIG. 27C. Once the energy has been applied, the fistula 384 mayform coagulated region 386 and seal fistula 384, as shown in FIG. 27D.

In addition to sealing hollow body organs, any of the antenna variationsdescribed herein may additionally be used for the ablation of bonemetastases, e.g., osteoid osteomas, osteoblastomas, spinal metastases,etc. Due to the ablation region created by the curved microwave antenna,using the antenna is a viable option for treating such conditions or foralleviating pain. To effect microwave energy treatment in regions withinbone, the curved antenna may be inserted through a biopsy needle usingany of the methods described above.

As shown in one example in FIG. 28A, introducer 394 may be insertedwithin bone 390 through cortical bone and into, e.g., the medullarycavity 392. Once the distal end of introducer 394 has accessed cavity392, feedline 398 and curved antenna 396 may be inserted throughintroducer 394 and deployed within cavity 392. This example illustratesantenna 396 as having multiple curved antennas; however, a single curvedantenna or a plurality of curved antennas may be used depending upon thedesired results. Once antennas 396 have been deployed within cavity 392,the antennas may be used to ablate regions of the soft core of bone 390,e.g., to de-nerve the region for pain reduction, or to kill cancerouscells, etc. FIG. 28B shows another example in which a number of separatecurved antennas 400, 402 may be introduced into cavity 392 to ablate theregion. Antennas 400, 402 may be introduced and positioned adjacently toone another in a parallel configuration, as shown or described above orusing any number of guide assemblies described above, or at variousangles relative to one another. Although only two antennas are shown inthe FIG. 28B, any number of antennas may be utilized as practicable. Anynumber of antenna configurations may also be utilized, as describedabove, as practicable depending upon the desired ablation results.

The applications of the microwave antenna and methods of use discussedabove are not limited to regions of the body but may include any numberof further treatment applications. Other treatment sites may includeareas or regions of the body such as other organ bodies. Moreover,various other antenna shapes and partial shapes may be utilized beyondwhat is described herein. Modification of the above-described assembliesand methods for carrying out the invention, and variations of aspects ofthe invention that are obvious to those of skill in the art are intendedto be within the scope of the claims.

We claim:
 1. An electrosurgical energy delivery system, comprising: amicrowave generator configured to supply microwave energy; a RFgenerator configured to supply RF energy; a power supply coupled to themicrowave generator and the RF generator, the power supply configured tosupply power to each of the microwave and RF generators; a microwaveantenna operably coupled to the microwave and RF generators by afeedline, the microwave antenna extending distally from the feedline andterminating at a distal tip; a first output coupled to the microwavegenerator and configured to deliver microwave energy to at least aportion of the microwave antenna; a second output coupled to the RFgenerator and configured to deliver RF energy to the distal tip of themicrowave antenna such that the distal tip of the microwave antenna cutstissue contacted by the distal tip using RF energy supplied from the RFgenerator upon advancement of the microwave antenna through tissue; anda first electrical line electrically connecting the first output to themicrowave antenna and a second electrical line electrically connectingthe second output to the microwave antenna at the distal tip.
 2. Thesystem of claim 1, further comprising at least one switch for selectingbetween the delivery of microwave energy and RF energy.
 3. The system ofclaim 2, wherein the first and second outputs deliver the microwaveenergy and the RF energy simultaneously.
 4. The system of claim 1,wherein the microwave antenna includes an insulated portion disposedproximal to the distal tip thereof.
 5. The system of claim 4, whereinthe microwave generator is configured to deliver microwave energy to theinsulated portion of the microwave antenna.
 6. An electrosurgicalantenna assembly, comprising: an antenna configured to deliver at leastone of microwave energy or RF energy to tissue; a feedline operablycoupling the antenna to a supply of microwave energy and to a supply ofRF energy, the antenna extending distally from the feedline andterminating at a distal tip, wherein the feedline is configured todeliver RF energy to the distal tip of the antenna in an amountsufficient to cut tissue contacted by the distal tip; and a firstelectrical line electrically connecting the supply of microwave energyto the antenna and a second electrical line electrically connecting thesupply of RF energy to the antenna at the distal tip.